Automatic swimming pool cleaners of the type that move about the underwater surfaces of a swimming pool are driven by many different kinds of systems. A variety of different pool cleaner drive devices in one way or another harness the flow of water, as it is drawn (or in some cases pushed) through the pool cleaner by the pumping action of a remote pump for debris collection purposes, to create forward pool cleaner movement. Some of the many kinds of water-driven automatic pool cleaners are those driven in various ways by turbines, which translate water movement into rotational motion, and those driven in various ways by oscillators, which move back and back and forth by virtue of Bernoulli's principle, a motion which can be converted into intermittent unidirectional rotation and harnessed in various ways.
Various water-driven automatic pool cleaners of the prior art are four-wheel structures supported on underwater surfaces by wheels. Wheel rotation by linkage to a turbine or other drive mechanism causes propulsion in such prior art devices. Various problems and shortcoming exist in such prior devices.
Among the problems and shortcomings not adequately addressed are failures of certain kinds of cleaners to provide complete cleaning coverage. Obtaining complete coverage is particularly difficult or problematic for swimming pools having certain kinds of surfaces, surface shapes or obstacles. Complete coverage, and thus satisfactory cleaning, are difficult to obtain when the pumping pressure generated by the pump is weak, such that the driving force of a pool cleaner is seriously diminished. Various automatic pool cleaners of the prior art have insufficient speed and strength of movement, and this creates and exacerbates problems of weak cleaning ability. Some problems, failures or difficulties occur when pool cleaners get hung up or caught at an area where its driving wheels are unable to contact the underwater pool surfaces, or are at least unable to engage such surfaces with sufficient traction to allow movement of the pool cleaner. For some cleaners of the prior art, steering (that is, the motions taken by pool cleaners in order to change directions) can be problematic, particularly on certain kinds of surfaces and when speed is low and the steering and propulsion forces that are generated are low.
Various advances have been made over the years, but there remains a need for an automatic water-driven pool cleaner, particularly of wheeled kind, having improved function in movement and in cleaning ability.